Meteorology and atmospheric science terminology · MLC-0110

Meteorology and atmospheric science terms: S (367)

• S1) South or 2) Snow
• SABSatellite Analysis Branch, part of NESDIS NESDIS: National Environmental Satellite, Data and Information...
• Sacramento Soil Moisture Accounting ModelA continuous soil moisture accounting model with spatially lumped parameters that simulates runoff within a...
• SafetyNETInmarsat-C SafetyNET is an internationally adopted, automated satellite system for promulgating weather...
• Saffir-Simpson Hurricane Wind ScaleThe Saffir-Simpson Hurricane Wind Scale is a 1 to 5 categorization based on the hurricane's intensity at the...
• salinityIn oceanography, conductivity is measured and converted to salinity by a known functional relationship...
• SAME(Specific Area Message Encoding) - A tone alert system which allows NOAA Weather Radio receivers equipped...
• SAMEXStorm and Mesoscale Ensemble Experiment
• Sampling FrequencyThe rate at which sensor data is read or sampled.
• sandstormParticles of sand carried aloft by strong wind. The sand particles are mostly confined to the lowest ten...
• Santa Ana WindIn southern California, a weather condition in which strong, hot, dust-bearing winds descend to the Pacific...
• sastrugiRidges of snow formed on a snow field by the action of the wind.
• SAT1. Satellite (imagery)
• Satellite Hydrology ProgramA NOHRSC program that uses satellite data to generate areal extent of snow cover data over large areas of the...
• SATLSatellite
• saturation vapor pressureThe vapor pressure of a system, at a given temperature, wherein the vapor of a substance is in equilibrium...
• SAWRSSupplementary Aviation Reporting Station - the SAWRS program addresses the concerns of users who depend on...
• S-Band RadarThese were in use as network radars in the National Weather Service prior to the installation of the WSR 88-D...
• SBCAPESurface Based CAPE; CAPE calculated using a Surface based parcel.
• SBNDSouthbound
• SBSDSubside
• SCStratocumulus
• SCASmall Craft Advisory
• scatteredWhen used to describe precipitation (for example: "scattered showers") - Area coverage of convective weather...
• scatteringThe process in which a beam of light is diffused or deflected by collisions with particles suspended in the...
• SCTScattered
• scudSmall, ragged, low cloud fragments that are unattached to a larger cloud base and often seen with and behind...
• SESoutheast
• sea breezeA thermally produced wind blowing during the day from a cool ocean surface onto the adjoining warm land...
• Sea Breeze Convergence ZoneThe zone at the leading edge of a sea breeze where winds converge. The incoming air rises in this zone, often...
• sea fogCommon advection fog caused by transport of moist air over a cold body of water.
• sea iceAny form of ice found at sea which has originated from the freezing of sea water (sea ice does NOT include...
• sea level pressureThe sea level pressure is the atmospheric pressure at sea level at a given location. When observed at a...
• Sea Surface TemperaturesThe term refers to the mean temperature of the ocean in the upper few meters.
• sea-breeze frontThe leading edge of a sea breeze, whose passage is often accompanied by showers, a wind shift, or a sudden...
• SeasThe combination of both wind waves and swell. Used to describe the combination or interaction of wind waves...
• Secondary Ambient Air Quality StandardsAir quality standards designed to protect human welfare, including the effects on vegetation and fauna...
• Secondary PollutantPollutants generated by chemical reactions occurring within the atmosphere. Compare primary pollutant.
• Second-Day FeetIn hydrologic terms, the volume of water represented by a flow of one cubic foot per second for 24 hours...
• Sector BoundaryIn solar-terrestrial terms, in the solar wind, the area of demarcation between sectors, which are large-scale...
• Sector VisibilityThe visibility in a specific direction that represents at least a 45º arc of a horizontal circle.
• Sectorized Hybrid ScanA single reflectivity scan composed of data from the lowest four elevation scans. Close to the radar, higher...
• SecuriteA headline within National Weather Service high seas forecasts transmitted via the GMDSS to indicate that no...
• Sediment Storage CapacityIn hydrologic terms, the volume of a reservoir planned for the deposition of sediment.
• SeepageIn hydrologic terms, the interstitial movement of water that may take place through a dam, its foundation, or...
• seicheA standing wave oscillation of water in large lakes usually created by strong winds and/or a large barometric...
• SELA watch cancellation statement issued to terminate a watch before its original expiration time.
• SELSSevere Local Storm
• SELYSoutheasterly
• Sensible Heat FluxThe flux of heat from the earth's surface to the atmosphere that is not associated with phase changes of...
• Sentinel-1 (S1)A European Space Agency satellite remote sensing mission which images with a 5cm wavelength Synthetic...
• Sentinel-2 (S2)A European Space Agency satellite remote sensing mission which images with a multi-spectral scanner.
• Separation EddyAn eddy that forms near the ground on the windward or leeward side of a bluff object or steeply rising...
• Serial DerechoType of derecho that consists of an extensive squall line which is oriented such that the angle between the...
• SERNSoutheastern
• Service HydrologistThe designated expert of the hydrology program at a WFO.
• servo loopIn radar meteorology, a generic description of hardware needed to remotely control the motion of the antenna...
• setThe direction towards which a current is headed. For example, a current moving from west to east is said to...
• Set-upThe process whereby strong winds blowing down the length of a lake cause water to "pile up" at the downwind...
• Severe IcingThe rate of ice accumulation on an aircraft is such that de-icing/anti-icing equipment fails to reduce or...
• Severe Local StormA convective storm that usually covers a relatively small geographic area, or moves in a narrow path, and is...
• Severe Local Storm WatchAn alert issued by the National Weather Service for the contiguous U.S. and its adjacent waters of the...
• Severe ThunderstormA thunderstorm that produces a tornado, winds of at least 58 mph (50knots), and/or hail at least 1" in...
• Severe Thunderstorm WarningThis is issued when either a severe thunderstorm is indicated by the WSR-88D radar or a spotter reports a...
• Severe Thunderstorm WatchThis is issued by the National Weather Service when conditions are favorable for the development of severe...
• Severe Weather AnalysisThis WSR-88D radar product provides 3 base products (reflectivity (SWR), radial velocity (SWV), and spectrum...
• Severe Weather Potential StatementThis statement is designed to alert the public and state/local agencies to the potential for severe weather...
• Severe Weather ProbabilityThis WSR-88D radar product algorithm displays numerical values proportional to the probability that a storm...
• Severe Weather StatementA National Weather Service product which provides follow up information on severe weather conditions (severe...
• SEWDSoutheastward
• SFCSurface
• SfericIn solar-terrestrial terms, a transient electric or magnetic field generated by any feature of lightning...
• SGSnow grains
• SGFNTSignificant
• shallow fogFog in which the visibility at 6 feet above ground level is 5/8ths statute mile or more and the apparent...
• SHARSSubtle Heavy Rainfall Signature
• shearVariation in wind speed (speed shear) and/or direction (directional shear) over a short distance within the...
• Sheet FlowIn hydrologic terms, flow that occurs overland in places where there are no defined channels, the flood water...
• sheet iceIce formed by the freezing of liquid precipitation or the freezing of melted solid precipitation (see snow...
• shelf cloudA low, horizontal wedge-shaped arcus cloud, associated with a thunderstorm gust front (or occasionally with a...
• SHFTShift
• SHLWShallow
• shore iceIn hydrologic terms, an ice sheet in the form of a long border attached to the bank or shore.; border ice.
• Short Term ForecastA product used to convey information regarding weather or hydrologic events in the next few hours.
• Short Wave FadeIn solar-terrestrial terms, a particular ionospheric solar flare effect under the broad category of sudden...
• Short-Fuse WarningA warning issued by the NWS for a local weather hazard of relatively short duration. Short-fuse warnings...
• short-range forecastA configuration of the National Water Model (NWM) that runs hourly and produces hourly deterministic...
• Short-Term Prediction Research and TransitionA NASA- and NOAA-funded activity to transition experimental/quasi-operational satellite observations and...
• Short-Term Prediction Research and Transition Center - Land Information SystemProvides high-resolution (~3 km) gridded soil moisture products in real-time to support regional and local...
• ShortwaveAlso known as Shortwave Trough; a disturbance in the mid or upper part of the atmosphere which induces upward...
• shortwave radiationIn solar-terrestrial terms, shortwave radiation is a term used to describe the radiant energy emitted by the...
• Shortwave TroughAlso called Shortwave; A disturbance in the mid or upper part of the atmosphere which induces upward motion...
• Showalter Index(Abbrev. SWI) - a stability index used to determine thunderstorm potential. The SWI is calculated by lifting...
• showerA descriptor, SH, used to qualify precipitation characterized by the suddenness with which they start and...
• SHRARain showers
• SHRASshowers
• SHRTShort
• SHRTWVShortwave - a disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it...
• SHSNSnow showers
• SHWRShower
• SidelobeA secondary energy maximum located outside the main radar beam. Typically, it contains a small percentage of...
• SIGMETSignificant Meteorological Advisory
• signal-to-noise ratioA ratio that measures the comprehensibility of data, usually expressed as the signal power divided by the...
• significant wave heightThe mean or average height of the highest one third of all waves in a swell train or in a wave generating...
• Significant Weather OutlookA narrative statement produced by the National Weather Service, frequently issued on a routine basis, to...
• SIGWXSignificant Weather
• Single Cell ThunderstormThis type of thunderstorm develops in weak vertical wind shear environments. On a hodograph, this would...
• SITOR(SImplex Teletype Over Radio) - a means of transmitting text broadcasts over radio. The U.S. Coast Guard...
• Sky ConditionUsed in a forecast to describes the predominant/average sky condition based upon octants (eighths) of the sky...
• SKYWARNA nationwide network of volunteer weather spotters who report to and are trained by the National Weather...
• SLSea Level
• SLDSolid
• sleet(PL) - Sleet is defined as pellets of ice composed of frozen or mostly frozen raindrops or refrozen partially...
• Sleet WarningIssued when accumulation of sleet in excess of 1/2" is expected; this is a relatively rare scenario. Usually...
• SLGTSlight
• Slight ChanceIn probability of precipitation statements, usually equivalent to a 20 percent chance.
• Slight Risk(of severe thunderstorms)- Severe thunderstorms are expected to affect between 2 and 5 percent of the area. A...
• sling psychrometerAn instrument used to measure the water vapor content of the atmosphere in which wet and dry bulb...
• SLOSlow
• SLOSH(Sea, Lake and Overland Surges from Hurricanes) - A computer model run by the National Hurricane Center (NHC)...
• SLPSea Level Pressure
• SLT1. Slight (as in "slight chance")
• SLYSoutherly
• SM1) Statute Miles
• SMAThe Soil Moisture Accounting Model.
• Small CraftThere is no precise definition for small craft. Any vessel that may be adversely affected by Small Craft...
• Small Craft Advisory(SCA) - An advisory issued by coastal and Great Lakes Weather Forecast Offices (WFO) for areas included in...
• Small Craft Should Exercise CautionPrecautionary statement issued to alert mariners with small, weather sensitive boats.
• Small hailTechnically used to refer to snow pellets or graupel.
• Small Stream FloodingIn hydrologic terms, flooding of small creeks, streams, or runs.
• smogOriginally smog meant a mixture of smoke and fog. Now, it means air that has restricted visibility due to...
• smoke(abbrev. K) Smoke in various concentrations can cause significant problems for people with respiratory...
• Smoke DispersalDescribes the ability of the atmosphere to ventilate smoke. Depends on the stability and winds in the lower...
• Smoke ManagementThe use of meteorology, fuel moisture, fuel loading, fire suppression and burn techniques to keep smoke...
• Smoothed Sunspot NumberAn average of 13 monthly RI numbers, centered on the month of concern.
• SMW(Special Marine Warning) - A warning product issued for potentially hazardous weather conditions usually of...
• SNsnow
• SNOTELSNOw TELemetry - An automated network of snowpack data collection sites. The Natural Resources Conservation...
• SnowPrecipitation in the form of ice crystals, mainly of intricately branched, hexagonal form and often...
• Snow Accumulation and Ablation ModelIn hydrologic terms, a model which simulates snow pack accumulation, heat exchange at the air-snow interface...
• Snow AdvisoryThis product is issued by the National Weather Service when a low pressure system produces snow that may...
• Snow CoreA sample of either freshly fallen snow, or the combined old and new snow on the ground. This is obtained by...
• Snow CorniceA mass of snow or ice projecting over a mountain ridge.
• Snow Data Assimilation SystemA physically based, mass conserving snow water equivalent (SWE) model.
• snow densityThe mass of snow per unit volume which is equal to the water content of the snow divided by its depth.
• Snow DepthThe combined total depth of both the old and new snow on the ground.
• Snow FlurriesSnow flurries are an intermittent light snowfall of short duration (generally light snow showers) with no...
• snow grainsPrecipitation consisting of white, opaque ice particles usually less than 1 mm in diameter.
• Snow PackSame as Snowcover; the combined layers of snow and ice on the ground at any one time.
• Snow PelletsPrecipitation, usually of brief duration, consisting of crisp, white, opaque ice particles, round or conical...
• snow pillow1) A window of snow deposited in the immediate lee of a snow fence or ridge. or
• snow showerA snow shower is a short duration of moderate snowfall. Some accumulation is possible.
• Snow SquallA snow squall is an intense, but limited duration, period of moderate to heavy snowfall, accompanied by...
• snow stakeA 1-3/4 inch square, semi-permanent stake, marked in inch increments to measure snow depth.
• Snow StickA portable rod used to measure snow depth.
• Snow Water EquivalentThe water content obtained from melting accumulated snow.
• SnowboardA flat, solid, white material, such as painted plywood, approximately two feet square, which is laid on the...
• SnowcoverAlso known as Snow Pack; the combined layers of snow and ice on the ground at any one time.
• snowflakeAn agglomeration of snow crystals falling as a unit.
• Snowmelt FloodingIn hydrologic terms, flooding caused primarily by the melting of snow.
• snowpackThe total snow and ice on the ground, including both the new snow and the previous snow and ice which has not...
• SNRSignal-to-Noise Ratio
• SNW1. snow
• SNWFLSnowfall
• SOIThe Southern Oscillation Index (SOI) has been developed to monitor the Southern Oscillation using the...
• soil moistureWater contained in the upper part of the soil mantle. This moisture evaporates from the soil and is the used...
• Solar CoordinatesIn solar-terrestrial terms, Central Meridian Distance (CMD). The angular distance in solar longitude measured...
• Solar cycleIn solar-terrestrial terms, the approximately 11-year quasi-periodic variation in frequency or number of...
• Solar MaximumIn solar-terrestrial terms, the month(s) during the solar cycle when the 12-month mean of monthly average...
• Solar MinimumIn solar-terrestrial terms, the month(s) during the solar cycle when the 12-month mean of monthly average...
• Solar NoonThe time of day at which the sun is the highest in the sky. This time varies through the year due to the...
• Solar Sector BoundaryIn solar-terrestrial terms, the apparent solar origin, or base, of the interplanetary sector boundary marked...
• Solar windThe outward flux of solar particles and magnetic fields from the sun. Typically, solar wind velocities are...
• SOLNSolution
• SOLNSsolutions
• solsticeEither of the two times per year when the sun is at its greatest angular distance from the celestial equator...
• SOOScience and Operations Officer
• soundingA set of data measuring the vertical structure of an atmospheric parameter (temperature, humidity, pressure...
• Southern Oscillation(SO) - a "see-saw" in surface pressure in the tropical Pacific characterized by simultaneously opposite sea...
• Southern Oscillation indexA numerical index measuring the state of the Southern Oscillation. The SOI is based on the (atmospheric)...
• Space Environment Center(SEC) - This center provides real-time monitoring and forecasting of solar and geophysical events, conducts...
• SPCStorm Prediction Center
• SPCLYEspecially
• SPD1) Speed
• Spearhead EchoA radar echo associated with a downburst with a pointed appendage extending toward the direction of the echo...
• Special Avalanche WarningIssued by the National Weather Service when avalanches are imminent or occurring in the mountains. It is...
• Special Fire WeatherMeteorological services uniquely required by user agencies which cannot be provided at an NWS office during...
• Special Marine Warning(SMW) A warning product issued for potentially hazardous weather conditions usually of short duration (up to...
• Special Tropical Disturbance StatementThis statement issued by the National Hurricane Center furnishes information on strong and formative...
• specific gravityThe ratio of the density of any substance to the density of water.
• specific humidityIn a system of moist air, the ratio of the mass of water vapor to the total mass of the system.
• specific yieldIn hydrologic terms, the ratio of the water which will drain freely from the material to the total volume of...
• Spectral densityA radar term for the distribution of power by frequency.
• Spectral Wave DensityOn a buoy report, energy in (meter*meter)/Hz, for each frequency bin (typically from 0.03 Hz to 0.40 Hz).
• Spectral Wave DirectionOn a buoy report, mean wave direction, in degrees from true North, for each frequency bin.
• Spectrum WidthThis WSR-88D radar product depicts a full 360 degree sweep of spectrum width data indicating a measure of...
• Spectrum Width Cross SectionThis WSR-88D radar product displays a vertical cross section of spectrum width on a grid with heights up to...
• Speed ShearThe component of wind shear which is due to a change in wind speed with height, e.g., southwesterly winds of...
• SPENESNESDIS Satellite Precipitation Estimates
• sphere calibrationReflectivity calibration of a radar by pointing the dish at a metal sphere of (theoretically) known...
• spillwayIn hydrologic terms, a structure over or through which excess or flood flows are discharged. If the flow is...
• Spillway CrestIn hydrologic terms, the elevation of the highest point of a spillway.
• Spin-UpSlang for a small-scale vortex initiation, such as what may be seen when a gustnado, landspout, or suction...
• SPKLSprinkle
• Split FlowA flow pattern high in the atmosphere characterized by diverging winds. Storms moving along in this type of...
• Splitting StormA thunderstorm which splits into two storms which follow diverging paths (a left mover and a right mover)...
• SPLNSSouthern Plains
• Sporadic EIn solar-terrestrial terms, a phenomenon occurring in the E region of the ionosphere, which significantly...
• SPOTNILIn solar-terrestrial terms, a spotless disk.
• SpottingOutbreak of secondary fires as firebrands or other burning materials are carried ahead of the main fire line...
• SprayAn ensemble of water droplets torn by the wind from an extensive body of water, generally from the crests of...
• SPRDSpread
• spring1. The season of the year comprising the transition period from winter to summer occurring when the sun is...
• spring tideA tide higher than normal which occurs around the time of the new and full moon.
• sprinkleVery light rain showers. Precipitation measurement is a trace.
• SPSSevere Weather Potential Statement
• SQLNSquall Line
• squallA strong wind characterized by a sudden onset in which the wind speed increases at least 16 knots and is...
• Squall lineA line of active thunderstorms, either continuous or with breaks, including contiguous precipitation areas...
• SRF(Surf Zone Forecast) - A National Weather Service routine or event driven forecast product geared toward...
• SRHStorm-Relative Helicity
• SRNSouthern
• SSSandstorm
• SSHSSaffir/Simpson Hurricane Scale
• SSTSea Surface Temperature
• STStratus
• St. Elmo's fireThe glow on a masthead produced by an extreme buildup of electrical charge. Unprotected mariners should...
• St Lawrence Freeze-Up OutlookA National Weather Service forecast product to keep mariners informed of the projected freeze-up date of ice...
• stabilityThe degree of resistance of a layer of air to vertical motion.
• stability indexThe overall stability or instability of a sounding is sometimes conveniently expressed in the form of a...
• StableAn atmospheric state with warm air above cold air which inhibits the vertical movement of air.
• stable boundary layerThe stably-stratified layer that forms at the surface and grows upward, usually at night or in winter, as...
• Stable CorePost-sunrise, elevated remnant of the temperature inversion that has built up overnight within a valley.
• Staccato LightningA Cloud to Ground (CG) lightning discharge which appears as a single very bright, short-duration stroke...
• stageThe level of the water surface of a river or stream above an established datum at a given location.
• Stair SteppingIn hydrologic terms, the process of continually updating river forecasts for the purpose of incorporating the...
• standard atmosphereA hypothetical vertical distribution of atmospheric temperature, pressure, and density that, by international...
• Standard Synoptic TimesThe times of 0000, 0600, 1200, and 1800 UTC. Also known as the main synoptic times.
• State Forecast ProductThis National Weather Service product is intended to give a good general picture of what weather may be...
• State Weather RoundupThis is a National Weather Service tabular product which provides routine hourly observations within the...
• Station IDFive-digit WMO Station Identifier used by the Buoy Data Center since 1976. ID's can be reassigned to future...
• station modelA specified pattern for plotting, on a weather map, the meteorological symbols that represent the state of...
• station pressureThe absolute air pressure at a given reporting station. The air pressure is directly proportional to the...
• Stationary FrontA front between warm and cold air masses that is moving very slowly or not at all.
• STBLStable
• steam fogFog formed when water vapor is added to air which is much colder than the source of the vapor. It may be...
• steepnessIn marine terms, on a buoy report, wave steepness is the ratio of wave height to wave length and is an...
• Steering CurrentsSame as Steering Winds; a prevailing synoptic scale flow which governs the movement of smaller features...
• Steering WindsSame as Steering Currents; A prevailing synoptic scale flow which governs the movement of smaller features...
• stepped leaderA faint, negatively charged channel that emerges from the base of a thunderstorm and propagates toward the...
• STFRStratus Fractus
• STGStrong
• Stilling basinIn hydrologic terms, a basin constructed to dissipate the energy of fast-flowing water (e.g., from a spillway...
• STJSubtropical Jet - this jet stream is usually found between 20° and 30° latitude at altitudes between 12 and...
• STLTSatellite
• STMStratiform
• STNRYStationary
• StoplogsIn hydrologic terms, large logs, timbers or steel beams placed on top of each other with their ends held in...
• StormAny disturbed state of the atmosphere, especially affecting the Earth's surface, and strongly implying...
• Storm DataThis National Climatic Data Center (NCDC) monthly publication documents a chronological listing, by states...
• Storm MotionThe speed and direction at which a thunderstorm travels.
• Storm RelativeMeasured relative to a moving thunderstorm, usually referring to winds, wind shear, or helicity.
• Storm Relative Mean Radial Velocity Map(SRM): This WSR-88D radar product depicts a full 360º sweep of radial velocity data with the average motion...
• Storm Relative Mean Radial Velocity Regi(SRR): This WSR-88D radar product depicts a 27 nm by 27 nm region of storm relative mean radial velocity...
• Storm ScaleReferring to weather systems with sizes on the order of individual thunderstorms. See synoptic scale and...
• storm surgeAn abnormal rise in sea level accompanying a hurricane or other intense storm, whose height is the difference...
• Storm tideThe actual level of sea water resulting from the astronomic tide combined with the storm surge. Most NWS...
• Storm Total PrecipitationThis radar image is an estimate of accumulated rainfall since the last time there was a one-hour, or more...
• Storm Tracking InformationThis WSR-88D radar product displays the previous, current, and projected locations of storm centroids...
• storm warningA warning of sustained surface winds, or frequent gusts, in the range of 48 knots (55 mph) to 63 knots (73...
• Storm WatchA watch for an increased risk of a storm force wind event for sustained surface winds, or frequent gusts, of...
• Stormwater DischargeIn hydrologic terms, precipitation that does not infiltrate into the ground or evaporate due to impervious...
• Straight-Line HodographThe name pretty well describes what it looks like on the hodograph. What causes this shape is a steady...
• Straight-line WindsGenerally, any wind that is not associated with rotation, used mainly to differentiate them from tornadic...
• stratiformHaving extensive horizontal development, as opposed to the more vertical development characteristic of...
• Stratiform Rings and BandsThese occur between the active convective bands of a hurricane outside of the eye wall. Inner stratiform...
• stratocumulusLow-level clouds, existing in a relatively flat layer but having individual elements. Elements often are...
• stratopauseThe boundary between the stratosphere and mesosphere.
• stratosphereThe region of the atmosphere extending from the top of the troposphere to the base of the mesosphere, an...
• Stratospheric OzoneIn the stratosphere, ozone has beneficial properties where it forms an ozone shield that prevents dangerous...
• stratusA low, generally gray cloud layer with a fairly uniform base. Stratus may appear in the form of ragged...
• Stream lineArrows on a weather chart showing wind speed and direction. The head of the arrow points toward where the...
• Stream ReachA significant segment of surface water that has similar hydrologic characteristics, such as a stretch of...
• streamflowIn hydrologic terms, water flowing in the stream channel. It is often used interchangeably with discharge.
• STRFMStratiform
• striationsGrooves or channels in cloud formations, arranged parallel to the flow of air and therefore depicting the...
• StrikeFor any particular location, a hurricane strike occurs if that location passes within the hurricane's strike...
• sublimationThe transition of a substance from the solid phase directly to the vapor phase, or vice versa, without...
• sublimation of iceThe transition of water from solid to gas without passing through the liquid phase.
• SubrefractionThe bending of the radar beam in the vertical which is less than under standard refractive conditions. This...
• subsidence1. A descending motion of air in the atmosphere occurring over a rather broad area.
• subsidence inversionA temperature inversion that develops aloft as a result of air gradually sinking over a wide area and being...
• SubstationA location where observations are taken or other services are furnished by people not located at NWS offices...
• subsurface storm flowIn hydrologic terms, the lateral motion of water through the upper layers until it enters a stream channel...
• Sub-synoptic LowEssentially the same as mesolow.
• Subtle Heavy Rainfall SignatureThis heavy rain signature is often difficult to detect on satellite. These warm top thunderstorms are often...
• Subtropical cycloneA non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This...
• Subtropical DepressionA subtropical cyclone in which the maximum 1-minute sustained surface wind is 33 knots (38 mph) or less.
• Subtropical Jet(Abbrev. STJ) - this jet stream is usually found between 20° and 30° latitude at altitudes between 12 and 14...
• Subtropical StormA subtropical cyclone in which the maximum 1-minute sustained surface wind is 34 knots (39 mph) or more.
• Suction VortexA small but very intense vortex within a tornado circulation. Several suction vortices typically are present...
• Sudden CommencementIn solar-terrestrial terms, an abrupt increase or decrease in the northward component of the geomagnetic...
• Sudden Impulse (SI+ or SI-)In solar-terrestrial terms, a sudden perturbation of several gammas in the northward component of the...
• sudden ionospheric disturbanceIn solar-terrestrial terms, HF propagation anomalies due to ionospheric changes resulting from solar flares...
• SUFSufficient
• summation principleThis principle states that the sky cover at any level is equal to the summation of the sky cover of the...
• summerTypically the warmest season of the year during which the sun is most nearly overhead. In the Northern...
• summer solsticeThe time at which the sun is farthest north in the Northern Hemisphere, on or around June 21.
• sun pillarA bright column above or below the sun produced by the reflection of sunlight from ice crystals.
• sun pointingAlignment of the radar antenna by locating the position of the sun in the sky, which has an exactly known...
• SunnyWhen there are no opaque (not transparent) clouds. Same as Clear.
• SunriseThe phenomenon of the sun's daily appearance on the eastern horizon as a result of the earth's rotation. The...
• sunsetThe phenomenon of the sun's daily disappearance below the western horizon as a result of the earth's...
• SunspotIn solar-terrestrial terms, an area seen as a dark spot on the photosphere of the sun. Sunspots are...
• Sunspot Group Classification• A: A small single unipolar sunspot or very small group of spots without penumbra.
• Sunspot NumberIn solar-terrestrial terms, a daily index of sunspot activity (R), defined as R = k (10 g + s) where S =...
• Super TyphoonTyphoon having maximum sustained winds of 130 knots (150 mph) or greater.
• supercellShort reference to Supercell Thunderstorm; potentially the most dangerous of the convective storm types...
• Supercell ThunderstormPotentially the most dangerous of the convective storm types. Storms possessing this structure have been...
• SupercoolTo cool a liquid below its freezing point without solidification or crystallization.
• Supercooled Liquid WaterIn the atmosphere, liquid water can survive at temperatures colder than 0 degrees Celsius; many vigorous...
• SuperrefractionBending of the radar beam in the vertical which is greater than sub-standard refractive conditions. This...
• Surcharge CapacityIn hydrologic terms, the volume of a reservoir between the maximum water surface elevation for which the dam...
• surf zoneArea of water between the high tide level on the beach and the seaward side of the breaking waves.
• Surf Zone Forecast(SRF) - A National Weather Service routine or event driven forecast product geared toward non-boating marine...
• Surface Energy BudgetThe energy or heat budget at the earth's surface, considered in terms of the fluxes through a plane at the...
• Surface impoundmentIn hydrologic terms, an indented area in the land's surface, such as a pit, pond, or lagoon.
• surface runoffIn hydrologic terms, the runoff that travels overland to the stream channel. Rain that falls on the stream...
• surface waterWater that flows in streams and rivers and in natural lakes, in wetlands, and in reservoirs constructed by...
• Surface Weather ChartAn analyzed synoptic chart of surface weather observations. A surface chart shows the distribution of...
• Surface-based ConvectionConvection occurring within a surface-based layer, i.e., a layer in which the lowest portion is based at or...
• surgeIn solar-terrestrial terms, a jet of material from active regions that reaches coronal heights and then...
• Sustained OverdraftIn hydrologic terms, long-term withdrawal from the aquifer of more water than is being recharged.
• Sustained WindWind speed determined by averaging observed values over a two-minute period.
• SVR1. Severe
• SVRLSeveral
• S/WShortwave - a disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it...
• SW1. Southwest
• SWDOn a buoy report, Swell Direction is the compass direction from which the swell wave are coming from.
• SWESnow Water Equivalent (the amount of water content in a snowpack or snowfall).
• SWEATSevere Weather ThrEAT index; a stability index developed by the Air Force which incorporates instability...
• swellWind-generated waves that have travelled out of their generating area. Swells characteristically exhibit...
• Swell DirectionThe direction from which the swells are propagating.
• SWHOn a buoy report, swell height is the vertical distance (meters) between any swell crest and the succeeding...
• SWLYSouthwesterly
• SWODY1The Day-1 Convective Outlook, sometimes called the "AC" is a guidance product issued by the Operational...
• SWODY2The Day 2 Convective Outlook is very similar to the Day 1 Outlook. It is issued only twice a day, at 08Z and...
• SWPOn a buoy report, Swell Period is the time (usually measured in seconds) that it takes successive swell wave...
• SWRNSouthwestern
• SWSSevere Weather Statement
• S/WVShortwave - a disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it...
• SWWDSouthwestward
• SXStability Index
• SXNSection
• Symmetric Double EyeA concentrated ring of convection that develops outside the eye wall in symmetric, mature hurricanes. The...
• synchronous detectionRadar processing that retains the received signal amplitude and phase but that removes the intermediate...
• SYNOPSynoptic - relating to the general weather pattern over a wide region, such as areas of high and low pressure...
• SynopsisA broad discussion of the weather pattern expected across any given area, generally confined to the 0-48 hour...
• synoptic codeRules and procedures established by the World Meteorological Organization(WMO) for encoding weather...
• synoptic scaleThe spatial scale of the migratory high and low pressure systems of the lower troposphere, with wavelengths...
• Synoptic TrackWeather reconnaissance mission flown to provide vital meteorological information in data sparse ocean areas...
• Synoptic WeatherWeather occurring over a wide region on time scales exceeding 12 hours.
• SYNSSynopsis
• synthetic aperture radarA radar mounted on a moving platform (aircraft or satellite) used for imaging. Since the radar antenna moves...
• Synthetic Aperture Radar River Ice SurveillanceAn experimental river ice mapping experiment using Synthetic Aperture Radar (SAR).
• SYSSystem
• syzygyIn solar-terrestrial terms, the instance (new moon or full moon) when the earth, sun, and moon are all in a...

367 of 3,164 terms in Meteorology and atmospheric science terminology (MLC-0110). Request the full dataset.